Change of sildenafil plasma concentrations after transition from bosentan to macitentan in pulmonary arterial hypertension

Introduction: Combination therapy of the phosphodiesterase-type 5 (PDE-5) inhibitor sildenafil and the endothelin receptor antagonist (ERA) bosentan may cause drug interactions in patients with pulmonary arterial hypertension (PAH). The objective of this study was to analyse plasma drug concentrations in PAH-patients during bosentan-sildenafil combination treatment and its changes after transition from bosentan to macitentan. Methods: Patients receiving a stable combination treatment of bosentan and sildenafil for at least one month were routinely assessed in our PAH centre. Routine assessments included demograp…